sha512-buffer tests: New module. * tests/test-sha512-stream.c: Renamed from tests/test-sha512.c. * modules/crypto/sha512-buffer-tests: New file, based on modules/crypto/sha512-tests. * modules/crypto/sha512-tests: Remove tests that are now in modules/crypto/sha512-buffer-tests. Test tests/test-sha512-stream.c instead of tests/test-sha512.c.